64

Theoretically it could take 25 minutes (or more), in practice it never did. Theoretically it could, because the C-64's built-in tape handling routines had a data rate of about 300 bit/s. That's 37.5 bytes per second, or almost 30 minutes for a full 64K. In practice, it never did, because the tape handling / decoding was done almost entirely in software, ...


50

First, many thanks for the great question. This may well be my favourite retrocomputing video of them all, so I contemplated having a look at the executable for a while myself. So, this is what I did: To download the audio, I went to the same YouTube video and used 4K Video Downloader (mainly because it clearly shows which audio is the original one, so that ...


19

The Card featured 256 bytes of ROM. Is there evidence documenting how the cassette program was stored? The evidence is right there in the PCB photo you added. The two MMI 6301 chips, labled APPLE A3 and APPLE A4, at position 3 and 4, are 256 by 4 PROMs. The same type, produced by Monolithic Memories, as used on the Apple 1 motherboard for the monitor ...


18

The Datassette has a digital interface, and since it is not meant to process audio signals at all, it allows directly writing sharp digital magnetic transitions to the tape, using a single monophonic read/write head. The written pulses are always written at same amplitude, so there is no variation between equipment. Also when reading the transitions off the ...


18

Yes, cassettes were common, they took ages, and they were error prone. In Europe, disk drives for the ZX Spectrum and Commodore 64 were uncommon. It's the same for cartridge games for the C64. The market for the 8-bit micros in the 80s in the UK was driven by price, so the cassette interfaces were the majority here. (BBC Micros with floppy drives were common ...


13

The beep comes from the OS ROM, and it is actually derived from the timing of the start and stop bits of each byte shifted into POKEY, this is determined from the interaction of the interrupts generated. The frequency output is nominally half of the operating bit rate, e.g. approximately 960Hz for a 19200 baud transmission (e.g. from a disk drive at normal ...


9

It doesn't make any difference. The border colour changes between red and cyan whenever the tape loading routine detects a change in level between low and high, and this happens many times over the period that a video frame is being sent to the display (from top to bottom), producing the stripes. Static stripes would just mean that the level changes are ...


9

TL;DR: Yes, it could take up to 25 minutes (from tape) and it could fail due to many reasons, like record dropout or bad adjusted head. Long story: It was pretty common to distribute software and games on tape cassettes. Cartridges were rare, much rarer than the cassettes. And it was not only for Commodore - almost every home computer of the early 80s' has ...


5

Both the DFS and the ADFS did indeed reserve memory for themselves at startup, increasing PAGE; this memory was used to hold the current catalogue and other bookkeeping. For adapting existing tape software two observations are helpful: almost nothing on the BBC was a multiload; and you can turf the [A]DFS out of memory if you don't intend to use it again. ...


4

As other answers note, the basic tape and disk routines on the C64 were notoriously slow. Commercial game releases usually were on tape, but tended to use a "fastloader" routine to bring the loading times down to something vaguely sane. The loader routine also served as an excuse to display a loading screen and play music while you waited - and ...


4

Did they actually sell commercial/legal software for Commodore 64 and other early home computers on tapes on shelves in stores? For full price? I remember that the Oric 1/Atmos had a fast and a slow mode. Slow mode was 300 bauds. But it wasn't the default. Default was "fast" (2400 bauds). Both modes were built-in (there were slightly faster custom ...


4

A partial answer that I nevertheless hope contributes: It doesn’t sound like an Acorn machine because the data isn’t in chunks, and probably isn’t an Amstrad because that uses the same physical encoding as the Spectrum so the lead-in tone for samples 3 & 4 would be the same as for 1 & 2. By ear, my best guess for Tape 4 is a Commodore but I couldn’t ...


4

A "perfect" result would be obtained if the stripes move at the same pace you can observe when SAVEing a program, that is, a signal with a period of exactly 2168*2 T-states, which means 807.2 Hz. (T-state information taken from https://faqwiki.zxnet.co.uk/wiki/Spectrum_tape_interface ) As the screen you see is the sampled version of what the TV is ...


3

I believe the datasette had the ADC built in, so it could then transmit digital signals to the computer. By optimising for digital output, the unit should have been more reliable, compared to a conventional tape player which would have bias settings for a more accurate output of analogue sound data.


3

What I've heard from people who should know, is that it's simply a form of error checking, not error correction. The data is always read twice, but the second time it simply checks that the data read from the tape is what is already in RAM. Most other systems, even at that time, used a CRC to do the same job more efficiently. Of course, you can ...


3

The datassette doesn't have the bias circuit on recording, because on digital data wasn't necessary, and also has sensors that informed if the motor was engaged. Also the power supply was from the computer so no batteries or extra plugs were involved. On the reproducing part a circuit designed to process a digital signal doesn't introduces unnecessary stages ...


3

Commercial software was certainly released on cassette tapes. This was a very common practise in the days of early micro-computers since floppy disk drives were very expensive, and some micro-computers did not have floppy disk drive interfaces. For these computers, audio cassette was the only means of data storage. I can remember having to wait for many ...


3

As to how such a device might work, look at the standard Commodore tape encoding, common to the PET, Vic-20, C64 and more. The timings actually vary very slightly between those computers when writing, but I'm going to use the archetypal timings given by The Complete Commodore Inner Space Anthology, page 97. A program file on tape consists of: a leader — a ...


3

You most likely wrote your early experimental programs in the BASIC language, using Timex’s ROM-resident BASIC interpreter and line editor. Cassette-tape storage would have been accessed using the SAVE and LOAD commands in the interpreter’s immediate mode. Commercial software, however, would nearly always get written in machine language — to gain the best ...


2

I've made a couple of discoveries after a night's sleep. The CoCo still reads the leader length from a RAM address, but its address is two bytes higher in memory than in the Dragon 32: 0199 ** THESE BYTES ARE MOVED DOWN FROM ROM 0200 *** INIT DESCRIPTION 0201 * VALUE 0202 008F CMPMID RMB 1 18 *PV 1200/2400 HERTZ PARTITION 0203 0090 CMP0 RMB 1 24 *PV UPPER ...


2

I found this question because I was getting the same symptoms on my Tandy Model 100 when trying to load a text file that I had just (seemingly successfully) recorded to an MP3 file on a Zoom H1 recorder - the TEXT program would just sit there and wouldn't respond to anything, even turning the unit off and on didn't help and I had to reset it (didn't lose any ...


2

The other answers cover the historic reality, but I also think it’s worthwhile to illustrate what were the technical reasons for tapes to be “slow”. Audio tape as a medium is not “slow” and is quite data-dense, compared to what one might think based on what the home micros did back then. Compared to C64’s default rate, the tape can do 4 orders of magnitude ...


2

Can confirm, at least as a ballbark figure: I remember Impossible Mission taking 15 minutes to load. We just went out in the back yard and played in the meantime, being about 12 at the time. How did we put up with it? That was just how long it took. We didn't know how fast it would load 30-odd years in the future, so we didn't have that point of reference. I ...


2

Loading from cassette was very, very common and the default option for most 8-bit micro owners. The early micros like the C64 were reasonably affordable, and the fact you could hook them up to a regular television set as a monitor and an ordinary cassette deck to load data added to that affordability. Floppy drives were quite expensive and could double the ...


1

There are three ways an attempt to load a tape can fail: The loader reports success, but the data is incorrect. The loader reports failure and does not read correct data. The loader reports failure, but in fact loads the data correctly anyhow. Commodore's tape system does a very good job of preventing failure #1. Unfortunately, it writes two complete ...


1

Yes, although the disk releases here in North America weren't much faster. However with that said, awesome loader music made the waiting time far less painful. Cartridges may have been rare in the UK and most of Europe, however they were quite common in the early days of the computer here in North America. Most of the early Activision games for example were ...


1

Since the coco cassette interface used 1200 baud psk audio encoding in it, the tape format of the coco was 4X faster loading files from the tape and the tape files were 1/4th the size of similar files on atari and commodore systems, which used 300 baud afsk encoding. it became common to stack multiple files on a single tape. many magazines sold software ...


1

The panoply of software titles needing LOAD "" CODE to be loaded, is centred around the early ZX Spectrum years, 1982-1984. While LOAD "" also exists in the ZX81, the technique seems to be a remnant of a wide practice of writing games in assembly together with system variables, for that machine. That allied with the platform being ...


1

A Soviet computer Vector-06c did have a CP/M port called Micro-DOS that could work with a RAM disk only. Cold boot was either from a cassette tape or from ROM (cannot remember, though, if the operating system was a part of the on-board ROM, or one still had to plug an external ROM cartridge - either way, the bootloader could boot from both) The RAM disk ...


1

I learned there is a Danish company " B Cool Controls " that apparently are people from ex "Lanng Stelman" MEMAC, they probably have knowledge and experience of complete MEMAC, so they may help with any issues reg files and conversion


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